Tricks, Tips & Tweaks

Some Hi Fi tweaks to improve sound quality & disregard myths.

A few hints for those of you who would like to get the best out of your A/V system and have an open mind (worshippers of What, Which or Whose Hi Fi Magazines had better leave now) Bi-Wiring, this'll upset any audiophiles who slipped through my front page warning! For general home use, bi-wiring speakers offers absolutely no benefit whatsoever except for doubling the thickness of the speaker wire (which is why most people can hear an improvement). Those little electrons don't magically split into various frequencies and follow the path to the correct speaker (tweeter, woofer or whatever) so don't waste your time and money. Bi-wiring does work, however, when using separate amplification for various drivers. This is used mainly in super top end home systems using bi or tri amplification and in most professional sound re-enforcement systems. The reason it works well there is because each amplifier can be matched to the driver in terms of frequency and damping, it also reduces cross harmonics since an external crossover circuit separates the various frequency bands and points them to the matching amplifier/driver configuration. Bottom line? for normal home systems, use better speaker wire, it'll give you the same effect. Speaker Cables - Ah, my pet subject. I guess having formal qualifications in both metallurgy and electronics (albeit 30 years ago) I can get a fairly good handle on how those nasty little electrons wizz through cables from amplifier to speaker. Lets dispel some myths first - Forget uni-directional speaker wire, the signal to the speaker is alternating current and as such "vibrates" through the wire rather than travel linearly along it. If a speaker wire has a directional arrow on it, ask the salesman "why" and "how" it works. Thin wires for high frequency's and thicker wire for the low's - give me a break! The "skin effect", which is the name given to the phenomenon of high frequency AC signals traveling only on the outer skin of the conductors, only occurs to any significant effect in the megahertz region (just a tad higher than the 20kHz of standard CD's or even 192kHz DVD-A/SACD/Whatnext Formats. OFC or Oxygen Free Copper is a must. Well actually it is, but the very nature of copper wire manufacture means that virtually ALL copper wire is 99.9% + oxygen free, so the differences between different OFC's (99.9% or 99.9999%) is relatively moot. I won't go into the whys and wherefores of single crystalline structure wire, capacitance, inductance etc. except to say that an electrical engineer and audio specialist far more qualified than I, one Jim Rowe, who for many years was editor of Radio, TV and Hobbies held a double blind test using engineers and musicians whereby a high quality set of speakers was set up with an amplifier using several sets of speaker cables of about the same gauge. After several hours of listening and switching cables, no listener could accurately say which cable sounded better (or even different) from any other. You may go into a so-called "audiophile" store and swear blind that the super duper, silver coated, multi strand, variable thickness wire being demonstrated sounds better than the plain Jane standard wire but you're the victim of psychoacoustics, in other words you're being conned into spending way more money than needs be (not to mention lining the pockets of the "audiophile" store - you ought to see the markup on this stuff). The long and short of all this is quite simple - you need the wire to easily handle the current flow to the speakers, commensurate with the output of the amplifier. Obviously, the longer the run of wire, the thicker it needs to be so for those short runs (1 to 2 metres) don't go overboard and pay more than $6.00 a metre. For runs 5 metres and above you'll need to spend around $10.00 or more per metre. The exception is for surround speakers in a 5.1 or 6.1 system where the speakers are designated as "small". This is because all frequencies from around 85 Hz and below are sent to the LFE channel and as such the current sent to those surround speakers is significantly less since the lower bass frequencies are responsible for most of the energy transmitted through the speaker wire. So for a good connection to your speakers, count on spending around $6.00 to $10.00 per metre for your main speakers and $2.00 to $6.00 per metre for surrounds. If Alan Audiophile tries to tell you otherwise ask for a demonstration to justify the $20 per metre wire he's likely to try to flog you - and make sure when you're listening, that both sets of cables are heard at the same volume level (the louder sound always sounds superior to the ear). Next week we'll talk about bi-wiring and really upset the AW's. Making the most of your room acoustics. It doesn't matter how good your speakers are or how much you spend on them, they're always going to sound bad in an acoustically challenged room. To me, it just seems crazy to buy a pair of $10,000 speakers and not treat the room to provide the best environment for that investment be it for stereo or home theater sound. We had that problem when we moved to our new premises at Dural, as the rooms were almost square (the worst case scenario for creating standing waves for bass) we had almost no bottom end and the room echo was so bad the top end on all speakers sounded harsh. After consulting with the experts at Amber Technology, we came up with an acoustic treatment kit which totally transformed the sound of both our sound rooms. It's from a company called Primacoustic and is available as a kit to suit most rooms from 12 to 25 square meters (our rooms are around 30 square meters and it works just great). You can buy individual tiles although the London 12-a Kit at $1299 is the one we've used in both sound lounges. It not only dampens the echo, it has bass traps which improve the bass in terms of both overall volume and musicality. Not so much of a Tweak but an observation - Many customers come into the store sweating over which receiver or amplifier to incorporate into a system - more so than the speaker set-up - wrong way around! They speakers are responsible for around 75% of the total sound performance so the time and effort should be spent determining which speakers are the best for your particular needs. The receiver should lock itself into place depending on the features required, technical spec's of the speakers and main intended use, for example, in a similar price range Marantz may be better for music but Yamaha with it's superior decoding chip set may be better for Home Theater (although this isn't always the case). Any good Hi Fi dealer should be able to suggest the correct Amp/Receiver to match the chosen speakers, although you need to make sure there is no hidden agenda with the suggestion (such as that dealer importing the products recommended). If you need a reasonably honest opinion just e- mail us and we'll give you a relatively unbiased answer (I say relatively 'cause there are some brands I just dislike regardless) Furnishings - Ever wonder why, after purchasing Hi Fi from an up market "Audiophile" store, the system never sounds quite as good at home? Go back to the store and check their furnishings and dimensions. I'll bet there's no parallel walls in the room (hence no standing waves and better bass), I'll also bet that if you clap your hands in the room there'll be no "slap" echo (high frequency bounce). The reason for this is that the furnishings will be soft and hence absorb the higher frequencies. You can make the most of your system at home by realizing what's happening to the sound as it bounces around the room. If you have lots of glass windows, try for curtains rather than hard blinds and make sure you have some form of soft floor covering. If you have slate, tiles or polished wood, even a scatter rug in the center of the room will make an incredible difference to the sound. These sound absorbing soft furnishings will ensure you get an intimate sound rather than the nasty echoing that's so annoying. If you're building a dedicated sound room from scratch, do what the pro's do and ensure there are no parallel walls (check out the inside of your local movie theater next time) this will give you the ultimate in room acoustics. Finally, use a cotton bud to gently remove any wax lurking in your ears (I find an extra 4kHz of top end after a good clean out). Speaker Placement - Usually not a lot of thought goes into where the speakers are placed and once plonked down, they very rarely get moved. Speaker placement is critical and needs to be addressed to get the most out of your system. To understand the basics of speaker placement it's important to remember that the higher frequencies travel in a straight line, much like a flashlight beam whereas the lower the frequency, the less directional the sound until you get to the point where the sound is omni directional (the point at which the wavelength is longer than the distance between your ears - usually around 120 Hz). With these points in mind, it becomes obvious that the tweeters in the speakers should be at ear height or at least angled towards your ears to form an equilateral triangle, this will ensure that the sound stage is reasonably stable. The distance of the speakers from the wall will determine the quality of bass, as the lower frequencies are omni directional, they will "creep" around the box and tend to cancel themselves out to some degree as the speaker box moves further away from the wall, this will "tighten" the bass although diminish it's impact. As the speaker box gets closer to the wall, the bass will reflect off the wall and be re enforced, this tends to give a stronger bass albeit "sloppier" or less controlled. The secret is to move the box in and out from the wall until the best compromise is achieved. With a sub / satellite system the distance from the wall is no longer a major issue as most of the frequencies concerned are handled by the subwoofer. I may come back to this subject in more detail at a later date but all this thinking is giving me a headache so I'm going home for a bourbon and coke! This weeks tweak involves cabling, regular readers will know that I'm not a great fan of the smoke and mirrors tricks associated with expensive interconnects, most dealers push them 'cause it's an easy sale with plenty of profit. Good interconnects, however, are important and most systems can benefit by upgrading from the crappy leads that come standard with your DVD, CD or other source. As usual, some of the Pommie magazines go over the top and suggest spending 10% of the system price on interconnects (Darwin was correct in regards to isolationist inbreeding - that's why we came to Australia to evolve the gene pool). I would generally look at spending 10% of the SOURCE equipment on interconnects i.e. if your DVD was $1000 then you would need to spend around $100 on cabling - that includes both audio (fibre optic or digital co-ax) and video leads. In terms of video cabling, I wouldn't worry too much on a standard TV set whether you have to use S-Video or Component cables, there's not much between them and both are immensely superior to the standard composite video cable. If your TV has progressive scan, then the Component cable is preferable. For digital connections I prefer fibre optics, not because it sounds any better (there's no great difference) but simply because it makes a better connection. The cheap $20 fibre optics cables are OK but the $50 - $100 cables seem to offer more depth and definition - certainly worthwhile for better systems. Remember also to keep your cables as short as possible, the longer the cable, the more likely it is to pick up extraneous noise. Subwoofer settings. It's a difficult process trying to get a subwoofer to seamlessly integrate with the main speakers especially when it comes to music reproduction. Most surround sound receivers give the option of sending the bass information to the main speakers, the subwoofer or both. I've found that, regardless of the size of the main speakers, the best result is when the setting is on "both". In theory the subwoofer can be placed anywhere in the room but for optimal music reproduction I suggest the sub. be on the same wall as the main speakers and if it can't be placed between the speakers, make sure that it is no further away from the closest speaker than the distance between the speakers (trust me on this one). As a rule of thumb for the initial set up, place the phase switch (if available) at zero, the level to around 50% and the crossover to around 20% off the lowest setting (don't worry about the figures on the label - they're regularly inaccurate anyhow). Tweak the settings from there, until it sounds good to your ears then leave it alone.